The present invention relates to a tool and a method for replacing brake system components for automotive vehicles. Specifically, the present invention relates to a tool and a method for achieving proper orientation and alignment of fittings when installed on a replacement treadle valve so that the fittings align and couple with multiple tubing connections on the vehicle upon installation of the replacement treadle valve.
Automotive braking systems, especially the type commonly used on trucks and heavy equipment, often use pressurized air or hydraulic fluid as a working fluid. Some braking systems provide a centralized source of pressurized air connected through tubing to two or more brake cylinders, usually one brake cylinder located at each wheel of the vehicle. Each brake cylinder is adapted to receive air pressure from the centralized source and apply it to actuate the brake cylinder thereby resisting or stopping rotation of the adjacent wheel. A treadle valve, or xe2x80x9cfoot valvexe2x80x9d, is operated by application of force to a brake pedal that is coupled to and operates the treadle valve to controllably distribute air pressure from the centralized source to each brake cylinder. The treadle valve has a mounting flange to facilitate securing the treadle valve to the vehicle. Each brake cylinder is usually biased toward its original, disengaged position by a return spring or an opposing return cylinder for returning the brake cylinder to its original disengaged position after the brake pedal is released. The distribution of air pressure from the centralized source to the treadle valve, and from the treadle valve to the brake cylinders, is accomplished using tubing with threaded, airtight couplings at the treadle valve, centralized source and brake cylinders. Tubing may be made of metal, nylon, plastic, rubber or other materials that are well suited for supplying or delivering pressurized air because it can be shaped, bent and manipulated to conform to available surfaces of the vehicle, it is strong, relatively inexpensive and corrosion resistant. Treadle valves usually receive air from the centralized source through multiple air supply lines of tubing and distribute air to brake cylinders through multiple delivery lines of tubing.
The use of tubing to route air pressure from the centralized source to the treadle valve and distribute on to the brake cylinders also has its disadvantages. Many types of tubing used for delivering pressurized air are not very flexible and may easily kink or collapse if overstressed while bending. When the lengths of tubing and the treadle valve with fittings are originally installed, the lengths of tubing are coupled to the treadle valve and bent and aligned as necessary to allow proper make-up of the the fittings threadably inserted into the treadle valve to the tubing. Once installed, anchored to the vehicle frame or chassis and threadably coupled at its ends to the brake cylinder and the treadle valve, a length of tubing becomes very difficult to bend, redirect or manipulate during removal or replacement of the treadle valve. This problem is compounded by the use of pressure fittings or xe2x80x9celbowsxe2x80x9d that are used to couple the ends of the tubing to the treadle valve. Each fitting has a threaded male end for coupling to threaded ports in the treadle valve body, and a threaded female port, usually at a 90-degree angle with the threaded male end, for receiving the seal nut on the end of the length of tubing. In addition to the angle of the fitting itself, the angular orientation of the female port of the fitting, and consequently that of the mating end of the tubing, depends on how far the threaded male end of the fitting is threaded into the port in the treadle valve body. When a worn or defective treadle valve requires replacement, the defective treadle valve is unbolted at its mounting flange from its fixed location near the brake pedal, and the ends of the lengths of tubing are disconnected from the fittings in the treadle valve body by reversing the threaded male seal nuts out of the threaded female ports in the fittings. After removal of the worn or defective treadle valve with fittings still intact, the fittings must each be removed from the worn or defective treadle valve body and each fitting, or new fitting, must then be threaded into the replacement treadle valve body prior to its installation on the vehicle. Since the inflexible tubing is difficult to bend and manipulate, replacement of a worn or defective treadle valve becomes problematic. In order to minimize bending and manipulation of tubing, it is important that each fitting be threaded into the replacement treadle valve body so that it provides the same position and angular orientation for receiving the threaded male seal nut as it previously had on the worn or defective treadle valve that is replaced. After the treadle valve is decoupled from up to eight or more lengths of tubing (e.g., four providing air pressure from the centralized source to the treadle valve and four providing air pressure from the treadle valve to the brake cylinders upon braking), great care must be taken in removing the fittings from the worn or defective treadle valve and installing them or their replacements in their corresponding coupled positions relative to the replacement treadle valve. If the threaded male end of each fitting is not threaded into its port in the treadle valve body to achieve its prior angular orientation, an attempt to bend and align the end of the tubing with the fitting after installation of the replacement treadle valve may result in tubing kinks or collapse, requiring costly and time-consuming replacement of the tubing.
There is a need for a tool that facilitates the replacement of the treadle valve with each fitting threaded into the corresponding port of the replacement treadle valve in exactly the same orientation and alignment as they previously had on the worn or defective treadle valve. There is a further need for a tool that facilitates proper orientation and alignment of fittings installed on a replacement treadle valve in order to prevent damage during coupling to tubing upon installation of the treadle valve. There is a need for a tool that enables the user to properly orient and align fittings on a replacement treadle valve in their permanent positions before the replacement treadle valve is installed on the vehicle. There is a need for a method of removing a fitting from a worn or defective treadle valve and installing it in its previous orientation and alignment on the replacement treadle valve. This tool may be used with a gauge that measures angular orientation of each fitting before the fitting is removed from the worn or defective treadle valve that is being replaced so that the fitting can be oriented and aligned in the same position when it is subsequently installed on the replacement treadle valve before the replacement treadle valve is installed on the vehicle. It is desirable that the tool of the present invention be easily used by mechanics with equipment commonly found in repair shops. It is also desirable that such a tool be designed for use with a common bench vise.
It is desirable that the tool be ergonomically designed to facilitate easy removal of the fittings from the worn or defective treadle valve and easy installation with proper orientation and alignment on the replacement treadle valve. It is desirable that the tool of the present invention be designed so that the worn or defective treadle valve and the replacement treadle valve can be mounted on the tool side by side to facilitate transfer of fittings from the worn or defective treadle valve to the replacement treadle valve, and to ensure that fittings of differing configurations are properly transferred to installed in the corresponding port of the replacement treadle valve. It is desirable that the tool of the present invention allows both the worn or defective treadle valve and the replacement treadle valve to generally be rotated about their central axes so that fittings threaded into ports located at various positions around the body of the treadle valve can be easily measured, removed, re-installed and properly aligned in the corresponding ports on the replacement treadle valve.
The present invention is a treadle valve vise having two rotatable couplings, each rotatable coupling having a means for securing a treadle valve to the rotatable coupling. These rotatable couplings may be rotatively coupled to a fixed support member that can be mounted in a common bench vise.
The two rotatable couplings each rotate about an axis, and the axis about which the first rotatable coupling rotates is generally parallel to the axis about which the second rotatable coupling rotates. The rotatable coupling may be comprised of a rotatable inner shaft that is received within and rotates within the hollow interior of a stationary pipe that is secured to a support member. The stationary outer pipe of the rotatable coupling may be circumferentially welded to a plate to provide the necessary structural support for the two rotatable couplings. The rotatable coupling is coupled to the rotatable inner shaft so that the treadle valve, when secured to the rotatable coupling, can be easily rotated for providing ready access for removal of the fittings from the worn or defective treadle valve and installation of fittings in the corresponding ports in the replacement treadle valve. The inner, rotatable shaft may be held axially in place by a retainer cap welded to the end of the inner rotatable shaft at the end of the rotatable shaft opposite the rotatable coupling.
The present invention also comprises one or more locking systems that rotatively lock each rotatable coupling in place to prevent rotation of the rotatable coupling while the user secures the treadle valves to the rotatable coupling, measures the alignment or orientation of the fittings on the worn or defective treadle valve, or removes and transfers fittings from the worn or defective treadle valve to the replacement treadle valve. The locking system may be a locking pin that is inserted through aligned pin holes in the inner rotatatable shaft and the outer stationary pipe. When the locking pin is inserted through the aligned holes in the concentric shaft and pipe, the inner shaft is rotatively locked into place until the locking pin is removed. When the locking pin is removed, the treadle valves can be further rotated for measurement, removal or reinstallation of other fittings.
The present invention provides a method of replacing a treadle valve comprising decoupling of all lengths of tubing from the fittings of the worn or defective treadle valve and securing the worn or defective treadle valve and the replacement treadle valve on rotatable couplings, one adjacent and generally parallel to the other. The treadle valves can then be rotated side by side such that the worn or defective treadle valve and the replacement treadle valve are always rotatively positioned to present corresponding sides of the two treadle valves to the user. The user can then measure the position of each fitting, remove the fitting from the worn or defective treadle valve and install the fitting or its replacement in the same orientation on the replacement treadle valve. After all fittings have been installed or replaced on the replacement treadle valve in their proper orientation and alignment, the replacement treadle valve is decoupled from the rotatable coupling, installed on the vehicle and easily coupled to lengths of tubing without kinking or collapse of tubing. It should be noted that an adjustable sliding T-bevel can be used to measure the angle of a fitting prior to its removal from the worn or defective treadle valve in order to ensure proper orientation and alignment after transfer to the replacement treadle valve.